/*
 * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
 *
 * You are hereby granted a non-exclusive, worldwide, royalty-free license to use,
 * copy, modify, and distribute this software in source code or binary form for use
 * in connection with the web services and APIs provided by Facebook.
 *
 * As with any software that integrates with the Facebook platform, your use of
 * this software is subject to the Facebook Developer Principles and Policies
 * [http://developers.facebook.com/policy/]. This copyright notice shall be
 * included in all copies or substantial portions of the software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.facebook.appevents.ml

import kotlin.math.min

class MTensor(private var shape: IntArray) {
  private var capacity: Int = getCapacity(shape)
  var data: FloatArray = FloatArray(capacity)
    private set
  val shapeSize: Int
    get() = shape.size

  fun getShape(i: Int) = shape[i]

  /**
   * Reshape the shape
   *
   * @param shape to reshape
   */
  fun reshape(shape: IntArray) {
    this.shape = shape
    val newCapacity = getCapacity(shape)
    val newData = FloatArray(newCapacity)
    System.arraycopy(data, 0, newData, 0, min(capacity, newCapacity))
    data = newData
    capacity = newCapacity
  }

  companion object {
    private fun getCapacity(shape: IntArray) = shape.reduce { acc, i -> acc * i }
  }
}
